Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 a3ff1db78421ee27…

MALICIOUS

Office (OLE) / .XLSX

1.39 MB
MD5: bf85ccbe67f3c5b40b631f0cb15b0267 SHA-1: 6dcc4a3d9de50329c25ad15fd356a806e0236425 SHA-256: a3ff1db78421ee274cc7c162352e3bc9815b772a0f608b53bea1c7d5f35cdbeb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an encrypted OOXML file that contains embedded OLE objects, with a high-confidence detection of an Equation Editor OLE object. This object appears to carry a payload anomaly, suggesting it's designed to exploit a vulnerability within the Equation Editor. The file's structure and the presence of the Equation Editor OLE object strongly indicate it's an exploit carrier.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.